Use like malloc(). Memory allocated with this function is reported in
Redis INFO memory, used for keys eviction according to maxmemory settings
and in general is taken into account as memory allocated by Redis.
You should avoid using malloc().
Use like calloc(). Memory allocated with this function is reported in
You should avoid using calloc() directly.
Use like realloc() for memory obtained with <code>RedisModule_Alloc()</code>.
Use like free() for memory obtained by <code>RedisModule_Alloc()</code> and
<code>RedisModule_Realloc()</code>. However you should never try to free with
<code>RedisModule_Free()</code> memory allocated with malloc() inside your module.
Like strdup() but returns memory allocated with <code>RedisModule_Alloc()</code>.
Return heap allocated memory that will be freed automatically when the
module callback function returns. Mostly suitable for small allocations
that are short living and must be released when the callback returns
The returned memory is aligned to the architecture word size
at least word size bytes are requested, otherwise it is just
aligned to the next power of two, so for example a 3 bytes request is
4 bytes aligned while a 2 bytes request is 2 bytes aligned.
There is no realloc style function since when this is needed to use the
pool allocator is not a good idea.
The function returns NULL if <code>bytes</code> is 0.
Lookup the requested module API and store the function pointer into the
target pointer. The function returns <code>REDISMODULE_ERR</code> if there is no such
named API, otherwise <code>REDISMODULE_OK</code>.
This function is not meant to be used by modules developer, it is only
used implicitly by including redismodule.h.
Return non-zero if a module command, that was declared with the
flag "getkeys-api", is called in a special way to get the keys positions
and not to get executed. Otherwise zero is returned.
When a module command is called in order to obtain the position of
keys, since it was flagged as "getkeys-api" during the registration,
the command implementation checks for this special call using the
<code>RedisModule_IsKeysPositionRequest()</code> API and uses this function in
order to report keys, like in the following example:
Note: in the example below the get keys API would not be needed since
keys are at fixed positions. This interface is only used for commands
with a more complex structure.
Register a new command in the Redis server, that will be handled by
calling the function pointer 'func' using the RedisModule calling
The function returns <code>REDISMODULE_ERR</code> if the specified command
is already busy or a set of invalid flags were passed, otherwise
<code>REDISMODULE_OK</code> is returned and the new command is registered.
This function must be called during the initialization of the module
inside the <code>RedisModule_OnLoad()</code> function. Calling this function outside
of the initialization function is not defined.
The command function type is the following:
And is supposed to always return <code>REDISMODULE_OK</code>.
The set of flags 'strflags' specify the behavior of the command, and should
be passed as a C string compoesd of space separated words, like for
example "write deny-oom". The set of flags are:
"write": The command may modify the data set (it may also read
from it).
"readonly": The command returns data from keys but never writes.
"admin": The command is an administrative command (may change
replication or perform similar tasks).
"deny-oom": The command may use additional memory and should be
denied during out of memory conditions.
"deny-script": Don't allow this command in Lua scripts.
"allow-loading": Allow this command while the server is loading data.
"pubsub": The command publishes things on Pub/Sub channels.
"random": The command may have different outputs even starting
from the same input arguments and key values.
"allow-stale": The command is allowed to run on slaves that don't
serve stale data. Don't use if you don't know what
this means.
"no-monitor": Don't propoagate the command on monitor. Use this if
the command has sensible data among the arguments.
"fast": The command time complexity is not greater
than O(log(N)) where N is the size of the collection or
anything else representing the normal scalability
issue with the command.
"getkeys-api": The command implements the interface to return
the arguments that are keys. Used when start/stop/step
is not enough because of the command syntax.
"no-cluster": The command should not register in Redis Cluster
since is not designed to work with it because, for
example, is unable to report the position of the
keys, programmatically creates key names, or any
other reason.
Called by <code>RM_Init()</code> to setup the <code>ctx->module</code> structure.
This is an internal function, Redis modules developers don't need
to use it.
Return the current UNIX time in milliseconds.
Enable automatic memory management. See API.md for more information.
The function must be called as the first function of a command implementation
that wants to use automatic memory.
Create a new module string object. The returned string must be freed
with <code>RedisModule_FreeString()</code>, unless automatic memory is enabled.
The string is created by copying the <code>len</code> bytes starting
at <code>ptr</code>. No reference is retained to the passed buffer.
Create a new module string object from a printf format and arguments.
The returned string must be freed with <code>RedisModule_FreeString()</code>, unless
automatic memory is enabled.
The string is created using the sds formatter function sdscatvprintf().
Like <code>RedisModule_CreatString()</code>, but creates a string starting from a long long
integer instead of taking a buffer and its length.
The returned string must be released with <code>RedisModule_FreeString()</code> or by
enabling automatic memory management.
Like <code>RedisModule_CreatString()</code>, but creates a string starting from another
RedisModuleString.
Free a module string object obtained with one of the Redis modules API calls
that return new string objects.
It is possible to call this function even when automatic memory management
is enabled. In that case the string will be released ASAP and removed
from the pool of string to release at the end.
Every call to this function, will make the string 'str' requiring
an additional call to <code>RedisModule_FreeString()</code> in order to really
free the string. Note that the automatic freeing of the string obtained
enabling modules automatic memory management counts for one
<code>RedisModule_FreeString()</code> call (it is just executed automatically).
Normally you want to call this function when, at the same time
the following conditions are true:
1) You have automatic memory management enabled.
2) You want to create string objects.
3) Those string objects you create need to live after the callback
function(for example a command implementation) creating them returns.
Usually you want this in order to store the created string object
into your own data structure, for example when implementing a new data
type.
Note that when memory management is turned off, you don't need
any call to RetainString() since creating a string will always result
into a string that lives after the callback function returns, if
no FreeString() call is performed.
Given a string module object, this function returns the string pointer
and length of the string. The returned pointer and length should only
be used for read only accesses and never modified.
Convert the string into a long long integer, storing it at <code>*ll</code>.
Returns <code>REDISMODULE_OK</code> on success. If the string can't be parsed
as a valid, strict long long (no spaces before/after), <code>REDISMODULE_ERR</code>
is returned.
Convert the string into a double, storing it at <code>*d</code>.
Returns <code>REDISMODULE_OK</code> on success or <code>REDISMODULE_ERR</code> if the string is
not a valid string representation of a double value.
Compare two string objects, returning -1, 0 or 1 respectively if
a < b, a == b, a > b. Strings are compared byte by byte as two
binary blobs without any encoding care / collation attempt.
Append the specified buffere to the string 'str'. The string must be a
string created by the user that is referenced only a single time, otherwise
<code>REDISMODULE_ERR</code> is returend and the operation is not performed.
Send an error about the number of arguments given to the command,
citing the command name in the error message.
Example:
Send an integer reply to the client, with the specified long long value.
The function always returns <code>REDISMODULE_OK</code>.
Reply with the error 'err'.
Note that 'err' must contain all the error, including
the initial error code. The function only provides the initial "-", so
the usage is, for example:
and not just:
Reply with a simple string (+... rn in RESP protocol). This replies
are suitable only when sending a small non-binary string with small
overhead, like "OK" or similar replies.
Reply with an array type of 'len' elements. However 'len' other calls
to <code>ReplyWith*</code> style functions must follow in order to emit the elements
of the array.
When producing arrays with a number of element that is not known beforehand
the function can be called with the special count
<code>REDISMODULE_POSTPONED_ARRAY_LEN</code>, and the actual number of elements can be
later set with <code>RedisModule_ReplySetArrayLength()</code> (which will set the
latest "open" count if there are multiple ones).
When <code>RedisModule_ReplyWithArray()</code> is used with the argument
<code>REDISMODULE_POSTPONED_ARRAY_LEN</code>, because we don't know beforehand the number
of items we are going to output as elements of the array, this function
will take care to set the array length.
Since it is possible to have multiple array replies pending with unknown
length, this function guarantees to always set the latest array length
that was created in a postponed way.
For example in order to output an array like [1,[10,20,30]] we
could write:
Note that in the above example there is no reason to postpone the array
length, since we produce a fixed number of elements, but in the practice
the code may use an interator or other ways of creating the output so
that is not easy to calculate in advance the number of elements.
Reply with a bulk string, taking in input a C buffer pointer and length.
Reply with a bulk string, taking in input a RedisModuleString object.
Reply to the client with a NULL. In the RESP protocol a NULL is encoded
as the string "$-1rn".
Reply exactly what a Redis command returned us with <code>RedisModule_Call()</code>.
This function is useful when we use <code>RedisModule_Call()</code> in order to
execute some command, as we want to reply to the client exactly the
same reply we obtained by the command.
Send a string reply obtained converting the double 'd' into a bulk string.
This function is basically equivalent to converting a double into
a string into a C buffer, and then calling the function
<code>RedisModule_ReplyWithStringBuffer()</code> with the buffer and length.
Replicate the specified command and arguments to slaves and AOF, as effect
of execution of the calling command implementation.
The replicated commands are always wrapped into the MULTI/EXEC that
contains all the commands replicated in a given module command
However the commands replicated with <code>RedisModule_Call()</code>
the first items, the ones replicated with <code>RedisModule_Replicate()</code>
will all follow before the EXEC.
Modules should try to use one interface or the other.
This command follows exactly the same interface of <code>RedisModule_Call()</code>,
so a set of format specifiers must be passed, followed by arguments
matching the provided format specifiers.
Please refer to <code>RedisModule_Call()</code> for more information.
The command returns <code>REDISMODULE_ERR</code> if the format specifiers are invalid
or the command name does not belong to a known command.
This function will replicate the command exactly as it was invoked
by the client. Note that this function will not wrap the command into
a MULTI/EXEC stanza, so it should not be mixed with other replication
commands.
Basically this form of replication is useful when you want to propagate
the command to the slaves and AOF file exactly as it was called, since
the command can just be re-executed to deterministically re-create the
new state starting from the old one.
Return the ID of the current client calling the currently active module
The returned ID has a few guarantees:
The ID is different for each different client, so if the same client
executes a module command multiple times, it can be recognized as
having the same ID, otherwise the ID will be different.
The ID increases monotonically. Clients connecting to the server later
are guaranteed to get IDs greater than any past ID previously seen.
Valid IDs are from 1 to 2^64-1. If 0 is returned it means there is no way
to fetch the ID in the context the function was currently called.
Return the currently selected DB.
Change the currently selected DB. Returns an error if the id
is out of range.
Note that the client will retain the currently selected DB even after
the Redis command implemented by the module calling this function
returns.
If the module command wishes to change something in a different DB and
returns back to the original one, it should call <code>RedisModule_GetSelectedDb()</code>
before in order to restore the old DB number before returning.
Return an handle representing a Redis key, so that it is possible
to call other APIs with the key handle as argument to perform
operations on the key.
The return value is the handle repesenting the key, that must be
closed with <code>RM_CloseKey()</code>.
If the key does not exist and WRITE mode is requested, the handle
is still returned, since it is possible to perform operations on
a yet not existing key (that will be created, for example, after
a list push operation). If the mode is just READ instead, and the
key does not exist, NULL is returned. However it is still safe to
call <code>RedisModule_CloseKey()</code> and <code>RedisModule_KeyType()</code> on a NULL
value.
Close a key handle.
Return the type of the key. If the key pointer is NULL then
<code>REDISMODULE_KEYTYPE_EMPTY</code> is returned.
Return the length of the value associated with the key.
For strings this is the length of the string. For all the other types
is the number of elements (just counting keys for hashes).
If the key pointer is NULL or the key is empty, zero is returned.
If the key is open for writing, remove it, and setup the key to
accept new writes as an empty key (that will be created on demand).
On success <code>REDISMODULE_OK</code> is returned. If the key is not open for
writing <code>REDISMODULE_ERR</code> is returned.
Return the key expire value, as milliseconds of remaining TTL.
If no TTL is associated with the key or if the key is empty,
<code>REDISMODULE_NO_EXPIRE</code> is returned.
Set a new expire for the key. If the special expire
<code>REDISMODULE_NO_EXPIRE</code> is set, the expire is cancelled if there was
one (the same as the PERSIST command).
Note that the expire must be provided as a positive integer representing
the number of milliseconds of TTL the key should have.
The function returns <code>REDISMODULE_OK</code> on success or <code>REDISMODULE_ERR</code> if
the key was not open for writing or is an empty key.
If the key is open for writing, set the specified string 'str' as the
value of the key, deleting the old value if any.
writing or there is an active iterator, <code>REDISMODULE_ERR</code> is returned.
Prepare the key associated string value for DMA access, and returns
a pointer and size (by reference), that the user can use to read or
modify the string in-place accessing it directly via pointer.
The 'mode' is composed by bitwise OR-ing the following flags:
If the DMA is not requested for writing, the pointer returned should
only be accessed in a read-only fashion.
On error (wrong type) NULL is returned.
DMA access rules:
No other key writing function should be called since the moment
pointer is obtained, for all the time we want to use DMA access
to read or modify the string.
Each time <code>RM_StringTruncate()</code> is called, to continue with the DMA
access, <code>RM_StringDMA()</code> should be called again to re-obtain
a new pointer and length.
If the returned pointer is not NULL, but the length is zero, no
can be touched (the string is empty, or the key itself is empty)
so a <code>RM_StringTruncate()</code> call should be used if there is to enlarge
the string, and later call StringDMA() again to get the pointer.
If the string is open for writing and is of string type, resize it, padding
with zero bytes if the new length is greater than the old one.
After this call, <code>RM_StringDMA()</code> must be called again to continue
DMA access with the new pointer.
The function returns <code>REDISMODULE_OK</code> on success, and <code>REDISMODULE_ERR</code> on
error, that is, the key is not open for writing, is not a string
or resizing for more than 512 MB is requested.
If the key is empty, a string key is created with the new string value
unless the new length value requested is zero.
Push an element into a list, on head or tail depending on 'where' argumnet.
If the key pointer is about an empty key opened for writing, the key
is created. On error (key opened for read-only operations or of the wrong
type) <code>REDISMODULE_ERR</code> is returned, otherwise <code>REDISMODULE_OK</code> is returned.
Pop an element from the list, and returns it as a module string object
that the user should be free with <code>RM_FreeString()</code> or by enabling
automatic memory. 'where' specifies if the element should be popped from
head or tail. The command returns NULL if:
1) The list is empty.
2) The key was not open for writing.
3) The key is not a list.
Conversion from/to public flags of the Modules API and our private flags,
so that we have everything decoupled.
See previous function comment.
Add a new element into a sorted set, with the specified 'score'.
If the element already exists, the score is updated.
A new sorted set is created at value if the key is an empty open key
setup for writing.
Additional flags can be passed to the function via a pointer, the flags
are both used to receive input and to communicate state when the function
'flagsptr' can be NULL if no special flags are used.
The input flags are:
The output flags are:
On success the function returns <code>REDISMODULE_OK</code>. On the following errors
<code>REDISMODULE_ERR</code> is returned:
The key was not opened for writing.
The key is of the wrong type.
'score' double value is not a number (NaN).
This function works exactly like <code>RM_ZsetAdd()</code>, but instead of setting
a new score, the score of the existing element is incremented, or if the
element does not already exist, it is added assuming the old score was
zero.
The input and output flags, and the return value, have the same exact
meaning, with the only difference that this function will return
<code>REDISMODULE_ERR</code> even when 'score' is a valid double number, but adding it
to the existing score resuts into a NaN (not a number) condition.
This function has an additional field 'newscore', if not NULL is filled
with the new score of the element after the increment, if no error
Remove the specified element from the sorted set.
The function returns <code>REDISMODULE_OK</code> on success, and <code>REDISMODULE_ERR</code>
on one of the following conditions:
The return value does NOT indicate the fact the element was really
removed (since it existed) or not, just if the function was executed
with success.
In order to know if the element was removed, the additional argument
'deleted' must be passed, that populates the integer by reference
setting it to 1 or 0 depending on the outcome of the operation.
The 'deleted' argument can be NULL if the caller is not interested
to know if the element was really removed.
Empty keys will be handled correctly by doing nothing.
On success retrieve the double score associated at the sorted set element
'ele' and returns <code>REDISMODULE_OK</code>. Otherwise <code>REDISMODULE_ERR</code> is returned
to signal one of the following conditions:
There is no such element 'ele' in the sorted set.
The key is not a sorted set.
The key is an open empty key.
Stop a sorted set iteration.
Return the "End of range" flag value to signal the end of the iteration.
Setup a sorted set iterator seeking the first element in the specified
Returns <code>REDISMODULE_OK</code> if the iterator was correctly initialized
<code>REDISMODULE_ERR</code> is returned in the following conditions:
The value stored at key is not a sorted set or the key is empty.
The range is specified according to the two double values 'min' and 'max'.
Both can be infinite using the following two macros:
<code>REDISMODULE_POSITIVE_INFINITE</code> for positive infinite value
<code>REDISMODULE_NEGATIVE_INFINITE</code> for negative infinite value
'minex' and 'maxex' parameters, if true, respectively setup a range
where the min and max value are exclusive (not included) instead of
inclusive.
Exactly like <code>RedisModule_ZsetFirstInScoreRange()</code> but the last element of
the range is selected for the start of the iteration instead.
lexicographical range. Returns <code>REDISMODULE_OK</code> if the iterator was correctly
initialized otherwise <code>REDISMODULE_ERR</code> is returned in the
following conditions:
The lexicographical range 'min' and 'max' format is invalid.
'min' and 'max' should be provided as two RedisModuleString objects
in the same format as the parameters passed to the ZRANGEBYLEX command.
The function does not take ownership of the objects, so they can be released
ASAP after the iterator is setup.
Exactly like <code>RedisModule_ZsetFirstInLexRange()</code> but the last element of
Return the current sorted set element of an active sorted set iterator
or NULL if the range specified in the iterator does not include any
element.
Go to the next element of the sorted set iterator. Returns 1 if there was
a next element, 0 if we are already at the latest element or the range
does not include any item at all.
Go to the previous element of the sorted set iterator. Returns 1 if there was
a previous element, 0 if we are already at the first element or the range
Set the field of the specified hash field to the specified value.
If the key is an empty key open for writing, it is created with an empty
hash value, in order to set the specified field.
The function is variadic and the user must specify pairs of field
names and values, both as RedisModuleString pointers (unless the
CFIELD option is set, see later).
Example to set the hash argv[1] to the value argv[2]:
The function can also be used in order to delete fields (if they exist)
by setting them to the specified value of <code>REDISMODULE_HASH_DELETE</code>:
The behavior of the command changes with the specified flags, that can be
set to <code>REDISMODULE_HASH_NONE</code> if no special behavior is needed.
Unless NX is specified, the command overwrites the old field value with
the new one.
When using <code>REDISMODULE_HASH_CFIELDS</code>, field names are reported using
normal C strings, so for example to delete the field "foo" the following
code can be used:
Return value:
The number of fields updated (that may be less than the number of fields
specified because of the XX or NX options).
In the following case the return value is always zero:
The key was not open for writing.
The key was associated with a non Hash value.
Get fields from an hash value. This function is called using a variable
number of arguments, alternating a field name (as a StringRedisModule
pointer) with a pointer to a StringRedisModule pointer, that is set to the
value of the field if the field exist, or NULL if the field did not exist.
At the end of the field/value-ptr pairs, NULL must be specified as last
argument to signal the end of the arguments in the variadic function.
This is an example usage:
As with <code>RedisModule_HashSet()</code> the behavior of the command can be specified
passing flags different than <code>REDISMODULE_HASH_NONE</code>:
<code>REDISMODULE_HASH_CFIELD</code>: field names as null terminated C strings.
<code>REDISMODULE_HASH_EXISTS</code>: instead of setting the value of the field
expecting a RedisModuleString pointer to pointer, the function just
reports if the field esists or not and expects an integer pointer
as the second element of each pair.
Example of <code>REDISMODULE_HASH_CFIELD</code>:
Example of <code>REDISMODULE_HASH_EXISTS</code>:
The function returns <code>REDISMODULE_OK</code> on success and <code>REDISMODULE_ERR</code> if
the key is not an hash value.
Memory management:
The returned RedisModuleString objects should be released with
<code>RedisModule_FreeString()</code>, or by enabling automatic memory management.
Free a Call reply and all the nested replies it contains if it's an
array.
Wrapper for the recursive free reply function. This is needed in order
to have the first level function to return on nested replies, but only
if called by the module API.
Return the reply type.
Return the reply type length, where applicable.
Return the 'idx'-th nested call reply element of an array reply, or NULL
if the reply type is wrong or the index is out of range.
Return the long long of an integer reply.
Return the pointer and length of a string or error reply.
Return a new string object from a call reply of type string, error or
Otherwise (wrong reply type) return NULL.
Exported API to call any Redis command from modules.
On success a RedisModuleCallReply object is returned, otherwise
NULL is returned and errno is set to the following values:
EINVAL: command non existing, wrong arity, wrong format specifier.
EPERM: operation in Cluster instance with key in non local slot.
Return a pointer, and a length, to the protocol returned by the command
that returned the reply object.
Register a new data type exported by the module. The parameters are the
Please for in depth documentation check the modules API
documentation, especially the TYPES.md file.
name: A 9 characters data type name that MUST be unique in the Redis
Modules ecosystem. Be creative... and there will be no collisions. Use
the charset A-Z a-z 9-0, plus the two "-_" characters. A good
idea is to use, for example <code><typename>-<vendor></code>. For example
"tree-AntZ" may mean "Tree data structure by @antirez". To use both
lower case and upper case letters helps in order to prevent collisions.
encver: Encoding version, which is, the version of the serialization
that a module used in order to persist data. As long as the "name"
matches, the RDB loading will be dispatched to the type callbacks
whatever 'encver' is used, however the module can understand if
the encoding it must load are of an older version of the module.
For example the module "tree-AntZ" initially used encver=0. Later
after an upgrade, it started to serialize data in a different format
and to register the type with encver=1. However this module may
still load old data produced by an older version if the rdb_load
callback is able to check the encver value and act accordingly.
The encver must be a positive value between 0 and 1023.
typemethods_ptr is a pointer to a RedisModuleTypeMethods structure
that should be populated with the methods callbacks and structure
version, like in the following example:
rdb_load: A callback function pointer that loads data from RDB files.
rdb_save: A callback function pointer that saves data to RDB files.
aof_rewrite: A callback function pointer that rewrites data as commands.
digest: A callback function pointer that is used for <code>DEBUG DIGEST</code>.
free: A callback function pointer that can free a type value.
The digest and mem_usage* methods should currently be omitted since
they are not yet implemented inside the Redis modules core.
Note: the module name "AAAAAAAAA" is reserved and produces an error, it
happens to be pretty lame as well.
If there is already a module registering a type with the same name,
and if the module name or encver is invalid, NULL is returned.
Otherwise the new type is registered into Redis, and a reference of
type RedisModuleType is returned: the caller of the function should store
this reference into a gobal variable to make future use of it in the
modules type API, since a single module may register multiple types.
Example code fragment:
If the key is open for writing, set the specified module type object
as the value of the key, deleting the old value if any.
Assuming <code>RedisModule_KeyType()</code> returned <code>REDISMODULE_KEYTYPE_MODULE</code> on
the key, returns the moduel type pointer of the value stored at key.
If the key is NULL, is not associated with a module type, or is empty,
then NULL is returned instead.
the key, returns the module type low-level value stored at key, as
it was set by the user via <code>RedisModule_ModuleTypeSet()</code>.
Save an unsigned 64 bit value into the RDB file. This function should only
be called in the context of the rdb_save method of modules implementing new
data types.
Load an unsigned 64 bit value from the RDB file. This function should only
be called in the context of the rdb_load method of modules implementing
new data types.
Like <code>RedisModule_SaveUnsigned()</code> but for signed 64 bit values.
Like <code>RedisModule_LoadUnsigned()</code> but for signed 64 bit values.
In the context of the rdb_save method of a module type, saves a
string into the RDB file taking as input a RedisModuleString.
The string can be later loaded with <code>RedisModule_LoadString()</code> or
other Load family functions expecting a serialized string inside
the RDB file.
Like <code>RedisModule_SaveString()</code> but takes a raw C pointer and length
as input.
In the context of the rdb_load method of a module data type, loads a string
from the RDB file, that was previously saved with <code>RedisModule_SaveString()</code>
functions family.
The returned string is a newly allocated RedisModuleString object, and
the user should at some point free it with a call to <code>RedisModule_FreeString()</code>.
If the data structure does not store strings as RedisModuleString objects,
the similar function <code>RedisModule_LoadStringBuffer()</code> could be used instead.
Like <code>RedisModule_LoadString()</code> but returns an heap allocated string that
was allocated with <code>RedisModule_Alloc()</code>, and can be resized or freed with
<code>RedisModule_Realloc()</code> or <code>RedisModule_Free()</code>.
The size of the string is stored at '*lenptr' if not NULL.
The returned string is not automatically NULL termianted, it is loaded
exactly as it was stored inisde the RDB file.
In the context of the rdb_save method of a module data type, saves a double
value to the RDB file. The double can be a valid number, a NaN or infinity.
It is possible to load back the value with <code>RedisModule_LoadDouble()</code>.
In the context of the rdb_save method of a module data type, loads back the
double value saved by <code>RedisModule_SaveDouble()</code>.
In the context of the rdb_save method of a module data type, saves a float
value to the RDB file. The float can be a valid number, a NaN or infinity.
It is possible to load back the value with <code>RedisModule_LoadFloat()</code>.
float value saved by <code>RedisModule_SaveFloat()</code>.
Add a new element to the digest. This function can be called multiple times
one element after the other, for all the elements that constitute a given
data structure. The function call must be followed by the call to
<code>RedisModule_DigestEndSequence</code> eventually, when all the elements that are
always in a given order are added. See the Redis Modules data types
documentation for more info. However this is a quick example that uses Redis
data types as an example.
To add a sequence of unordered elements (for example in the case of a Redis
Set), the pattern to use is:
Because Sets are not ordered, so every element added has a position that
does not depend from the other. However if instead our elements are
ordered in pairs, like field-value pairs of an Hash, then one should
use:
Because the key and value will be always in the above order, while instead
the single key-value pairs, can appear in any position into a Redis hash.
A list of ordered elements would be implemented with:
Like <code>RedisModule_DigestAddStringBuffer()</code> but takes a long long as input
that gets converted into a string before adding it to the digest.
See the doucmnetation for <code>RedisModule_DigestAddElement()</code>.
Emits a command into the AOF during the AOF rewriting process. This function
is only called in the context of the aof_rewrite method of data types exported
by a module. The command works exactly like <code>RedisModule_Call()</code> in the way
the parameters are passed, but it does not return anything as the error
handling is performed by Redis itself.
This is the low level function implementing both:
Produces a log message to the standard Redis log, the format accepts
printf-alike specifiers, while level is a string describing the log
level to use when emitting the log, and must be one of the following:
"debug"
"verbose"
"notice"
"warning"
If the specified log level is invalid, verbose is used by default.
There is a fixed limit to the length of the log line this function is able
to emit, this limti is not specified but is guaranteed to be more than
a few lines of text.
Log errors from RDB / AOF serialization callbacks.
This function should be used when a callback is returning a critical
error to the caller since cannot load or save the data for some
critical reason.
Block a client in the context of a blocking command, returning an handle
which will be used, later, in order to block the client with a call to
<code>RedisModule_UnblockClient()</code>. The arguments specify callback functions
and a timeout after which the client is unblocked.
The callbacks are called in the following contexts:
Unblock a client blocked by <code>RedisModule_BlockedClient</code>. This will trigger
the reply callbacks to be called in order to reply to the client.
The 'privdata' argument will be accessible by the reply callback, so
the caller of this function can pass any value that is needed in order to
actually reply to the client.
A common usage for 'privdata' is a thread that computes something that
needs to be passed to the client, included but not limited some slow
to compute reply or some reply obtained via networking.
Note: this function can be called from threads spawned by the module.
Abort a blocked client blocking operation: the client will be unblocked
without firing the reply callback.
Return non-zero if a module command was called in order to fill the
reply for a blocked client.
reply for a blocked client that timed out.
Get the privata data set by <code>RedisModule_UnblockClient()</code>
Return a context which can be used inside threads to make Redis context
calls with certain modules APIs. If 'bc' is not NULL then the module will
be bound to a blocked client, and it will be possible to use the
<code>`RedisModule_Reply</code>*` family of functions to accumulate a reply for when the
client will be unblocked. Otherwise the thread safe context will be
detached by a specific client.
To call non-reply APIs, the thread safe context must be prepared with:
This is not needed when using <code>`RedisModule_Reply</code>*` functions, assuming
that a blocked client was used when the context was created, otherwise
no <code>RedisModule_Reply</code>* call should be made at all.
TODO: thread safe contexts do not inherit the blocked client
selected database.
Release a thread safe context.
Acquire the server lock before executing a thread safe API call.
This is not needed for <code>`RedisModule_Reply</code>*` calls when there is
a blocked client connected to the thread safe context.
Release the server lock after a thread safe API call was executed.
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